Vertical drop-out fuse



March 21, 1939. w Q, SCHULTZ 2,151,159

VERTICAL DROP-OUT FUSE Filed May 19, 1937 2 Sheets-Sheet l IN VENTOR.

BY H I ATTORNEY.

March 21, 1939. w. OISCHULTZ VERTICAL DROP-OUT FUSE Filed May 19, 1957 2 Sheets-Sheet 2 IN VENTOR.

ATTORNEY.

Patented Mar. 21, 1939 2,151,159 VERTICAL once-our rush William o. Schultz, South Milwaukee, Wlsa as Signor to Line Material (Company, South. Mll waulree, Wis, a corporation of Delaware Application May lit, 119%, Serial No. ll ltfill lfltl (Glalms. (@ll, gut-M l) This invention relates to drop-out type fuses for mounting on transformer terminal bushings. In certain types of transformers comprising a transformer winding and a metal casing enclosing the winding, 2. primary lead-in terminal e tends through the'top or" the casing and is provided with a bushing insulating the terminal from the casing. It is an object of this invention to provide a drop-out fuse structure adapted for mountlng'on such a transformer terminal, the structure including a fuse cartridge pivotallv and slidably mounted on the te inal and auto maticallv movable from circuit-closing position upon blowing of the cartridge.

More specifically it' is an object to provide a drop-out fuse mounted on and above transformer bushing for movement from circuit-dosing to open-circuit positions in a path extending verti callv at an angle and beyond the topot" the transformer casing and having its pa expulsion disposed at an acute angle relative to vertical plane and extending beyondthe outlines the transformer, thereby to direct metallic vapors expelled from the fuse away from the transiorm Other objects are to provide drop-cu" fuss which will produce a minimum torsional. upon the transformer bushing and lead-in termi- .nal when the fuse cartridge reaches its open-circuit position after the fuse has blown, is spring biased for sliding movezn so open-(tir cuit position, and in which a simple resilient flip= out spring strip having an integral tube-engaging portion is normally disposed in the path or" movement of the tube, thereby reducing the stress upon the fuse link to a minimum and extending the gapin the circuit before the tube moves.

Also it is an object to provide means interact ing between the fuse tube and its pivot and slid ing support for absorbing the reactive forces upon the tube when the fuse link is ruptured.

Still another object is to provide for a pivotally and slidably mounted drop-out fuse a manipulating ring at its free end, aligning means for assuring correct relative rotative relationship be= tween the ring and the fuse pivot when the fuse is operative for movement to and is positioned in circuit-closing position.

In connection with the foregoing last-noted object, it is also an object to provide for a dropout ruse having a fuse link-controlled flip-out spring, means for retaining the fuse link against displacement relative to the spring.

Other advantages will become apparent as the device disclosed herein is described.

in the drawings:

Fig. l. is a view in side elevation, partly in sectiou, showing the fuse in circuit-closing position.

Fig. 2 is a fragmentary view in side elevation showing the fuse in full lines in a horizontal position, and in broken lines in a position which it assumes after the has blown;

Fig. 3 is a sectional view taken on the line l l is a fragmentary view in side elevation on reduced scale illustrating a position in which the fuse may be supported. when the fuse linl; is operative for closing a circuit parts are identified by the same reference characters throughout the several views.

The transformer casing l, shown iragmentarlly, is provided with an insulation bushing ii surrouncling a lead in conductor extending into the casing and having a flanged terminal member 3 at the upper end of the bushing 2.

Mounted upon and secured to the member by means of a stud bolt .1 a current conducting support having an inclined base plate and a horizontally extending portion terminating in an inclined mounting plate l and relatively spaced hooked pivot arms 8 extending downwardly and outwardly from the arm. Secured to the plate 7! by a suitable means, such as screw bolt 9, is a ii-shaped. contact ill comprising two adjacent strips of hot spring arouse.

An insulator block l l is mounted upon the base' plate by means of a. bolt l2 and extends upwardly therefrom at an angle normal to the plate. Secured to the upper end of the block it and insulated therelov from the arms 9, is a spring contact plate l3 bent at M to provide a lead wire connecting portion and reversely curved at its floating end to provide a contact portion M, a retainer portion to and a plate-actuating portion it. As shown, the plate it is reinforced by a spring strip 68, each of which is secured to the block it by means of the bolt is.

The ffase cartridge comprises an insulating tube 2@ having at its upper end a metal ferrule 2|! provided with a radial flange 22, a pull ring 23 and a metal closure cap "2 The lower end of the tube is provided with a sleeve 25 sliolable thereon and having the major portion of its bore enlarged to provide space for the coil spring 26 which is disposed about the tube and within the bore of the sleeve 25. A collar ll normally holds the spring 2% under compression.

A flip-out spring strip 2%] is secured to the sleeve 25 by means of the threaded stud 30 and knurled nut ti and is bent at its lower end to all provide a hook portion 32 extending beneath the collar 21. The fuse link 23 is electrically connected with the cap 24 by means of its terminal head 33' and extends from the open end of the tube about the hook portion 32 and upwardly along the strip 29 to the stud 30 where it is anchored by means of the nut 3|.

The fact that the hook portion 32 is made arcuate as shown insures that no destructive abrasive action will be produced thereby upon the easily damaged fine wires of the fuse link zv'hen the latter is being connected to the sleeve The sleeve 25 is provided at its lower end with trunnions 25 receivable in the hooked portions of the pivot arms 8 and pivotally supporting the sleeve and tube upon the support 5. It will also be noted that the sleeve 25 is provided with lugs 38 positioned above and spaced from the trunnions 35. These lugs 36 serve as stops engageable with the lower margin of the U-shaped contact ll when the reactive expulsion forces upon the tube urge the tube upwardly, thereby preventing disengagement of the trunnions from the hooked arms 8. a

In circuit-closing position, illustrated in Fig. 1, the tube 20 extends angularly upwardly and from the axis of the trunnions and towards the vertical axis of the bushing 2. In this position, the sleeve 25 is positioned within and in electrical contact with the U-shaped contact i0, and the cap 24 is in electrical contact with the curved portion I 5 of the floating end of the contact springplate ii. The axis of the tube 20 preferably lies in a vertical plane coinciding substantially with the plane of the axis of the bushing 2. Thus, when the tube 2|! is moved into circuitcloaing position, the closing force will be in a iiiregtion laterally toward the axis of the bush- If the fuse link 33 is ruptured under abnormal conditions, the resilient flip-out strip 29 will immediately widen the gap at the ruptured portion and initiate withdrawal movement of the link from the tube 20. While the link is being withdrawn from the tube, the curved portion 22 of the ttrip 29 will be moved from beneath the collar 21, thereby to release the tube for sliding motion through the sleeve 25 under the influence of the spring 28. When the tube has been released as noted, the coil spring 28 will'move the tube downwardly at an 'angle extendingbeyond the casing land will separate the cap 24 from the spring strip or plate I 2.

In view of the fact that the tube 2. is disposed at a relatively sharp angle'extending downwardly, it will continue its sliding motion'through the sleeve until the fl'ange:22 on the ferrule 2| contacts the plateuflfi: The 'plat'e flis'secured to the sleeve 25 by niea'ns'of the "screw bolt II and is engageable with a tool (not shown) for removal of the cartridge from the arm 5. Since the sleeve is in frictional engagement with the U- shaped contact ID, the tube will be maintained in 1substantially the position shown in broken lines :1 Fig. 2. e

The fuse may be moved from the position indicated by the broken lines in Fig. 2 by engaging an operating tool (not shown) with the pull ring 23, and rotating the tube in a clockwise direction about the axis of trunnions 35 until it extends in the horizontal position shown in Fig. 2. In this position, the collar 21 engages the bottom of the support 5.

As soon as the tube is disposed in the horizontal position shown in Fig. 2, the manipulating tool (not shown) may be dise ed from the pull ring 23 and engaged with the plate 31, in a manner not shown, for the purpose of lifting the tube and sleeve from the hinge arms 8.

Attention is directed to the fact that the collar 21 on the lower end of the tube 20 is provided with a lug which extends into a notch ll in the lower end of the sleeve 25 and serves to require proper alignment of the pull ring 23 and sleeve. The lug N in cooperation with the slot ll prevents relative rotation between the tube 20 and sleeve 25 when force is exerted on the pull ring to move the tube to circuit-closing position.

The collar 21 is also provided with a pair of spaced laterally extending lugs 44 between which the spring strip 29 is positioned when held to the tube by the fuse link 3,3. The lugs 44 serve to prevent the fuse link from being accidentally displaced sidewise relative to the lower end of the strip 29 and also assist the lug 4D, to some degree,

in holding the tube 20 non-rotatively relative to the sleeve 25.

After dismounting of the cartridge from the arm 5, the damaged link 33 may be removed from the tube 20 in an obvious manner, and a new link placed therein by passing it through the upper end of the tube and about the lower end thereof and secured to the sleeve 25 as described, after the tube and sleeve are properly aligned and the curved end 32 of the spring strip 2| is disposed beneath the collar 21.

When a new fuse link hasbeen placed in the fuse tube, the fuse may be mounted on the pivot arms 8 by means of a manipulating stick (not shown) in engagement with the plate 31. Fig. 4 illustrates the position the tube first assumes after mounting upon arms 8. In this position, the lugs, upon the sleeve 25 contact with the projecting fingers 38 on the arms 8 and cooperate with the trunnions 35 to hold the tube as shown. The fingers 38 are inclined downwardly so that the tube will remain with its trunnions engaging the hooked arms 8 while in the position illustrated in Fig. 4. The fuse may be moved from the position shown in Fig. 4 to that shown in Fig. 1 by means of a manipulating stick in engagement with the pull ring 23. As the cap 24 moves to the circuit-closing position, it will engage the portion ll of the contact plate l3 and urge the plate and spring strip l8 upwardly until it passes the retainer portion it.

While I have described the operation of the device under the urge of the coil spring 28, it is obvious that it will move to open a circuit without the spring for the reason that the angle at which the fuse is disposed will permit it to freely slide in the sleeve 25 and for the further reason that the contact spring plate I! biases the tube toward sliding movement.

If it is desired to open the circuit under normal conditions and without destroying the link 33, it is only necessary to pull the fuse by means of the pull ring 23 in a clockwise direction relative to Fig. 1 about the trunnions 35 and to dispose the fuse in the position shown in Fig. 4

with the lugs 36 resting upon the fingers ll.

An arcing gap may be provided comprising a current conducting rod 45 secured in any suitable rnanner (not shown) to the transformercasing i and a second current conducting rod 48 in spaced relation to and above the rod 45 and secured to and in electrical contact with the comtact plate i2.

artists One of the advantages oi disposing the tube 29 at an angle, relativeto the casing i, is in proparatively simple structure, which may be manufactured' at a minimum cost, may be easily installed and manipulated, and, is eficient in operation.

ll claim:

1. In combination with a transformer casing having a lead-in surrounded by an insulating bushing, a pivot arm secured to the lead-in, said arm being mounted on and extending laterally from said bushing, an insulating block secured to the arm directly above said bushing, a terminal member secured to andiextending from the block, said arm and member being disposed in a vertical plane common to both and to the axis of said bushing, and an expulsion fuse cartridge pivotally supported on said arm and electrically connecting said arm and terminal, said cartridge being inclined upwardly from its pivotal support on said arm toward the axis of said bushing and downwardly away from said casing, whereby the path of gases expelled irom said cartridge will be away from said casing.

2. In combination with a transformer casing having a lead-in surrounded by an insulating bushing, a pivot arm secured to and extending laterally from said lead-in and bushing, an insulating block secured to said arm directly above said bushing, a terminal member secured to and extending from said block, said arm and member being disposed in a vertical plane common to both and to the axis or" said bushing. an expulsion ruse cartridge electrically connecting said arm and terminal, and a sleeve slidable on the cartridge and pivotally mounted on said arm, said cartridge being biased for sliding movement in said sleeve and being inclined upwardly from the pivotal support of said sleeve toward the axis of said bushing and downwardly away from said casing, whereby the path of gases expelled from said cartridge will be away from said casing,

3. In combination with an insulating support having spaced hooked pivot bearings each provided with a stop finger extending horizontally and downwardly from its corresponding bearing and having a terminal above said bearings, a fuse cartridge comprising an expulsion fuse tube provided at one end with a contact engaging saidterminal and at the other end with a sleeve having a pair of trunnions mounted in said bearings and a pair of lugs spaced above said trunnions for contact with said fingers, whereby to support said tube in a horizontal position when in open circuit position.

4. In combination with an insulating support having a supporting member terminating in spaced hooked pivot bearings each provided with a stop finger extending horizontally and downwardly from its corresponding bearing and hav ing a terminal above said bearings, of a fuse cartridge comprising an expulsion fuse tube provided at one end with a contact engaging said terminal and at the other end with a sleeve hav ing a pair of trunnions mounted in said bearings and a pair of lugs spaced above said trunnions for contact with said fingers when said tube is in open-circuit position, and contact means 'carried by said supporting member and extendin directly above said lugs when said tube is in circuit-closing position.

5. In combination with an insulating support having a supporting member terminating in spaced hooked pivot bearings and having a terminal above said bearings, a fuse cartridge comprising an expulsion fuse tube provided at one end with a contact engaging said terminal and at the other end with a sleeve having a pair oi trunnions mounted in said bearings and a lug on said sleeve spaced above said trunnions, and contact means carried by said supporting memher and extending directly above said lug when said tube is incircuit-closing position, said lug being engageable with said contact means to hold said sleeve in said bearings when said tube is in circuit-closing position.

6. In combination with an insulating support having a supporting member terminating in spaced hooked pivot bearings and having a ter minal above said bearings, a fuse cartridge comprising an expulsion fuse tube provided at one end with a contact engaging said terminal and at the other end with a sleeve slidable on the tube and having a pair of trunnions mounted in said bearings and a lug on said sleeve spaced above said trunnions, said tube being biased ior sliding movement in said sleeve, contact means carried by said supporting member and extending directly above said lug when said tube is in circuit-closing position, said lug being engageable with said contact to'hold said sleeve in said i bearing when said tube is in circuit-closing position, and a fuse link in said tube electrically connecting said contact and sleeve and normally restraining said tube against sliding movement.

7. In combination with an insulating support having a supporting member terminating in spaced hooked pivot bearings and having a terminal above said bearings, a fuse cartridge comprising an expulsion fuse tube provided at one end with a contact engaging said terminal and at the other end with a sleeve slidable on the tube and having a pair of trunnions mounted in said bearings and a lug on said sleeve spaced above said trunnions, said tube being biased-for I sliding movement in said sleeve, contact means carried by said supporting memberand extending directly above said lug when said tube is in circuit-closing position, said lug being engageable with said contact to hold said sleeve in said bearings when said tube is in circuit-closing position, and a fuse link in said tube electrically connecting said contact and sleeve and normally restraining said tube against sliding movement, said contact means being in frictional engagement with said sleeve, thereby to hold said tube against pivgtal movement in said bearings when moving to and disposed in open-circuit position.

7 8; In combination withan insulating support having a supporting member terminating in; spaced hooked pivot bearings an'dhaving a terminal above said bearings, a fuse cartridge comprising an expulsion fuse tube provided at one 'end'with a contact engaging said terminal and at the other end with a sleeve slidable on the tube ment in said sleeve, contact means carried by said supporting member, and a fuse link in said tube electrically connecting said contact and sleeve and normally restraining said tube against sliding movement, said contact means being in frictional engagement with said sleeve, thereby to hold said tube against pivotal movement in said bearings when moving to and disposed in open-circuit position. 9. In combination with an insulating suppor having a supporting member terminating in spaced hooked pivot bearings and having a terminal above said bearings, a fuse cartridge comprising an expulsion fuse tube provided at one end with a contact engaging said terminal and at the other end with a sleeve slidable on the tube and,

having a pair of trunnlons mounted in said bearings and 2. lug spaced above said trunnions, said tube being biased for sliding movement in said sleeve and being inclined upwardly from a horizontal plane extending through said trunnions and forwardly toward said support, contact means carried by said supporting member and extending directly above said lug when said tube is in circuit-closing position, and a fuse link in said tube electrically connecting said contact and sleeve and normally restraining said tube against sliding movement, said contact means being in frictional engagement with said sleeve, thereby to hold said tube against pivotal movement in said bearings when moving to and disposed in opencircuit position.

10. In combination with an insulating support having a supporting member terminating in spaced hooked pivot bearings and having a terminal above said bearings, a fuse cartridge com-' prising an expulsion fuse tube provided at one end with a contact engaging saidterminal and at the other end with a sleeve slidable on the tube and having a pair of trunnions mounted in said bearings, said tube being biased for sliding movement in said sleeve and being inclined. up-

wardly from a horizontal plane extending through said trunnions and forwardly toward said support, contact means carried by said supporting member, and a fuse link insaid tube electriealli connecting said contact and sleeve and normally restraining said tube against sliding movement, said contact means being in frictional engagement with said sleeve, thereby to hold said tube against pivotal movement in said bearings when moving to and disposed in open-circuit position.

11. In a drop-out fuse structure, the combination with an insulating support having a pivot arm and a terminal spaced therefrom, of a fuse cartridge comprising a tube having a contact at one end engaging said terminal, a collar secured to the other end of said tube, a sleeve slidable on. said tube between said contact and collar, said sleeve being pivotally supported on said arm, a flip-out spring strip secured to said sleeve and having an integral portion bent to be positioned beneathsaid collar, and a fuse link in said tube connecting said contact and sleeve and normally holding said spring strip portion beneath said collar, said tube being biased for sliding movement in said sleeve and normally restrained against said movement by said spring strip.

12. In a drop-out fuse, the combination with an insulating support having spaced relatively insulated current conducting members, of a fuse structure comprising a tube having a closure contact at one end and a sleeve on said tube at theother end thereof slidably supporting said tube and a fuse link connecting said contact and sleeve and normally holding said tube against sliding movement, said sleeve being pivotally mounted on one of said members and said contact normally engaged with the other of said members,,said tube being disposed at an angle relative to a vertical plane paralleling the pivotal mounting of said sleeve when in circuit-closing position and being slidable in a path coincident with said angle, and means on said support holding said sleeve against pivotal movement while said tube is sliding in said sleeve and when said tube has moved to open-circuit position.

13. In a drop-out fuse, the combination with an insulating support having spaced relatively insulated current conducting members, of a fuse electrically connecting said members and slidably and pivotally mounted on one of said members, said fuse being disposed angularly relative to a vertical plane paralleling the pivotal mounting of said fuse when in circuit-c1osing position, means holding said fuse against pivotal movement during sliding movement and when in open-circuit position, and current responsive means normally holding said fuse against sliding movement.

14. In combination with atransi'ormer casing having a. lead-in conductor surrounded by an insulating bushing, of a supporting arm mounted on said bushing and secured to said conductor, said arm extending laterally of said bushing and having a pivot bearing, an insulating block secured to said support and extending above said bearing, a resilient line terminal secured to said block remote from said support, a fuse connecting said support and terminal, said fuse being pivotally mounted in said bearing and slidable in a 1 path extending away from said casing, and means holding said fuse against pivotal movement while sliding in and subsequent to sliding in said path.

15. In a drop-out fuse of thdclass described, a support having a pivot bearing, a sleeve pivoted in said bearing, a tube slidable in said sleeve, a U-shaped contact frictionally embracing said sleeve, and 9. lug on said sleeve between said bearing and said contact engageable with said contact to hold said sleeve in said bearing when said tube is in circuit-closing position.

16. In a drop-out fuse of the class described, a support having a pivot bearing, a sleeve pivoted in said bearing, a tube slidable in said sleeve, a collar secured to said tube, a coil spring in said tube reacting between said sleeve and collar, a fuse link in said tube normally holding said tube against sliding motion, a contact frictionally embracing a portion of said sleeve, and a lug on said sleeve between said pivot bearing and contact engageable with said contact to hold said sleeve in said bearing when said tube is in circuitclosing position.

17. In a drop-out fuse of the class described, a support having an arm provided with a hook bearing, a sleeve having a trunnion mounted in said bearing, a tube carried by said sleeve, a contact member carried by said arm, and a lug on said sleeve between said bearing and said member and engageable with said member to hold said trunnion in said bearing.

18. In a. drop-out fuse of the class described, a support having an arm provided with a hook bearing intermediate its ends, a sleeve having a trunnion mounted in said bearing, a tube carried by said sleeve, a contact member carried by said am, and a lug on said sleeve between said bearing and said member and engageable with said member to hold said trunnion in said bearing, said lug being engageable with an end of said arm for supporting said tube in open-circuit position. i

19. In a drop-out fuse, the combination with a sleeve, of a tube slidable in said sleeve, a collar secured to said tube, a latching spring on said sleeve and engageable with said collar to hold said tube against sliding movement, and a fuse link in said tube normally holding said spring in engagement with said collar, said fuse link overlying said spring and said collar having means for holding said link against displacement rela-- tive to said spring.

20. In a drop-out fuse, the combination with a sleeve, of a tube slidable in said sleeve, a collar secured to said tube, a latching spring on said sleeve and engageable with said collar to hold said tube against sliding movement, a fuse link in said tube normally holding said spring in engagement with said collar, said fuse link overlying said spring and said collar having means for holding said link against displacement relative to said spring, and means coacting between said collar and sleeve for aligning said tube and sleeve rotatively.

21. In a drop-out fuse, the combination with a sleeve, of a tube slidable in said sleeve, a collar secured to said tube, a coil spring in said sleeve and disposed about said tube, a latching spring on said sleeve engageable with said collar to hold said coil spring under compression and said tube against sliding motion, and a fuse link in said tube normally holding said latch spring in engagement with said collar, said link overlying said latch spring and said collar having means for holding said link against displacement relative to said spring.

22. In a drop-out fuse, the combination with a sleeve, of a tube slidable in said sleeve, a collar secured to said tube, a coil spring in said sleeve and disposed about said tube, a latching spring on said sleeve engageable with said collar to hold said coil spring under compression and said tube against sliding motion, a fuse link in said tube normally holding said latch spring in engagement with said collar, said link overlying said latch Spring and said collar having means for holding said link against displacement relative to said spring, and means coacting between said collar and sleeve for aligning said tube and sleeve rotatively.

23. In a drop-out fuse, the combination with an insulating support having a pivot bearing, of a sleeve pivotally mounted in said bearing, a tube slidable in said sleeve, resilient means co-acting between said tube and sleeve to cause relative sliding movement, a latch spring on said sleeve for holding said tube against sliding motion, a fuse link in said tube holding said spring in engagement with said tube, a contact on said support frictionally engaging said sleeve, and a lug on said sleeve between said bearing and contact and engageable with said contact to hold said sleeve on said bearing.

24. In a drop-out fuse, the combination with an insulating support having a pivot bearing, of a sleeve pivotally mounted in said bearing, a tube slidable in said sleeve, resilient means co-acting between said tube and sleeve to cause relative sliding movement, a latch spring an said sleeve for holding said tube against sliding motion, a fuse link in said tube holding said spring in engagement with said tube, a contact on said support frictionally engaging said sleeve, a lug on said sleeve between said bearing and contact and engageable with said contact to hold said sleeve on said bearing, and means carried by said tube and coacting with said sleeve to hold said tube non-rotatively in said sleeve.

25. In a drop-out fuse, the combination with an insulating support having a pivot bearing, of a sleeve pivotally mounted insaid bearing, a tube slidable in said sleeve, resilient means co-acting between said tube and sleeve to cause relative sliding movement, a latch spring on said sleeve for holding said tube against sliding motion, a fuse link in said tube holding said spring in engagement with said tube, a contact on said support frictionally engaging said sleeve, a lug on said sleeve between said bearing and contact and engageable with said contact to hold said sleeve on said bearing, said link overlying said latch spring, and means carried by said tube for preventing displacement of said link relative to said spring.

26. In a drop-out fuse, the combination with an insulating support having a pivot bearing, of a. sleeve pivotally mounted in said bearing, a tube slidable in said sleeve, resilient means co-acting between said tube and sleeve to cause relative sliding movement, a latch spring on said sleeve for holding said tube against sliding motion, a fuse link in said tube holding said spring in engagement with said tube, a contact on said support frictionally engaging said sleeve, a ing on said sleeve between said bearing and contact and engageable with said contact to hold said sleeve on said bearing, said link overlying said latch spring, and means carried by said tube for-pre venting displacement of said link relative to said spring, said means including a portion coacting with said sleeve to hold said tube non-rotatively in said sleeve.

WILLIAM O. SCHULTZ. 

